1. Field of the Invention
The present invention relates to a file system which manages buffers considering the input and output of system data such as a swap. Input and output performance of the system is improved through buffer management of each application object of each input and output of data in the file system.
2. Description of the Related Art
The increase of data handled by large scale numerical computations and processing of moving pictures has greatly increased in the past few years. The programs for handling the computations and processing are complicated and require a larger capacity storage device. Therefore, a computer system is now required to realize high speed processing of an extremely large amount of data. Meanwhile, new developments including high performance CPUs and the maturity of parallel processing techniques, etc., have brought about extraordinary improvements in the processing power of computers. Moreover, realization of extremely large capacity has also reached the secondary storage device and the main storage device of the computer. However, improvement in data transfer speed of the secondary storage device is rather small and is now considered a bottle-neck in the system.
The main storage device is usually utilized as a buffer of the secondary storage device to realize high speed input and output processings. However, since the capacity of the main storage device is limited, it is a must that effective management is performed on the limited buffer area.
In prior art systems, management of buffers has been carried out after the total buffer area has been divided into fixed length blocks. The buffer area allows coexistence of a swap file, a file used by the system such as dump, etc., and a file used by users such as a load module and data file, etc. Therefore, when a swap has been carried out and the dump has been acquired, the buffer area is totally occupied by the system. This generates a problem that a program cannot obtain a sufficient buffer area and input and output performance is deteriorated.
Moreover, when the swap is activated while a job is running by inputting and outputting a large amount of data totally occupying the buffer area, the system cannot reserve sufficient buffer area, resulting in a problem that swap processing generates a delay.
As described previously, prior art which employs conventional buffer management systems has a problem in that any data selected will occupy almost all the buffer area because the buffer area is competitively used for system data and user data. Thus, input and output performance is extremely lessened.